Thanks! The GenyMotion emulator worked perfectly. The "B4A AVD Manager/Emulator" gives an error on my machine... something about hardware acceleration.
After a while Genymotion stopped working.... I think it had something to do with me using the latest Oracle VirtualBox version.... So I tested other emulators.
BlueStacks 3 works quite well so far. Running the application from B4X will install it on the emulator.
I also tried NOX. I could get it working using B4A bridge. I didn't install YouWave because it is currently incompatible with VirtualBox (they say they are working on it).